Burr Puzzle

A burr puzzle, also known as an interlocking puzzle, consists of notched pieces of wood, plastic or metal that when put together creates a three-dimensional shape. This wood version is pretty simple and therefore relatively easy to make. It consists of 12 pieces of which 11 of are identical. The 12th piece is the similar except that it has a notch cut into the top surface which is the key to the solution.

In addition to the build instructions, I've also include STP and STL files for those inclined to go with the 3D printing route. You could also purchase a similar version from Amazon.

Lastly, it you can't figure it out from the pictures, I've included a video of the solution.

Enjoy making your puzzle!

Step 1: Tools/Materials

Tools:

Table Saw

Band Saw or Chisel

Nice ruler or Calipers

Pencil

Materials:

1x4 x 18" Long or 11/16" x 3.0" x 18" Long

Sand Paper

Paint/Stain (optional)

Step 2: Drawing of Completed Puzzle

You will be building to this drawing. Note that I assumed a 0.01" gap between all mating parts.

Step 3: Part 1 (Option 1)

I worked the dimensions for two different sizes of wood. Option 1 is for 11/16" thick wood which turned out to be the thickness I had on hand. Option 2 is for a more common size 1x4 which measures 0.75" x 3.5".

Start by cutting the 1x4 to 16". Note that 16" is more than you will need for the puzzle but I like to have spare pieces during the build process in case I make a mistake which is pretty common for me.

Step 4: Cut Width

Using a table saw, cut the width down to 3". Note that tolerances are critical for burr puzzles so slow down and make sure the cut is accurate. I used a scrap piece of wood and calipers to dial in my saw before making the final cuts.

Step 5: Channel

There are multiple ways to make the channel (router, gluing pieces together, etc.). I chose the manual route of running the board over my table saw multiple times with the blade height set to the midpoint of the board. This was pretty tedious process so you might want to opt for an alternative method. The slot did come out pretty nice. I had slight ridges that I cleaned up by sanding.

Step 6: Section Cuts

Set your table saw to 11/16" and start cutting pieces. The 16" length should give you about 19 pieces (7 more than you need). I hit knots on a couple of the sections which resulted in damaged pieces...glad I made extra!

Step 7: Part 2 (Option 1)

With one of the parts from the previous step, cut a notch per the drawing. I used a band saw for this cut but a hammer and chisel would work as well. You now have all the pieces for the puzzle.

Step 8: Assemble - Step 1

Place 2 blocks as shown on a flat surface.

Step 9: Assemble - Step 2

Place 2 more blocks opposite of the first two blocks.

Step 10: Assemble - Step 3

Place 2 blocks on the ledges of the four blocks.

Step 11: Assemble - Step 4

Place the next 2 blocks as shown.

Step 12: Assemble - Step 5

Repeat on the other side.

Step 13: Assemble - Step 6

Place the last "Part 1" block on the top and shift it to one side.

Step 14: Assemble - Step 7

Ok, here is the challenging part. You might need to refer to video but hopefully these pictures cover it. Push the highlighted block down as far as it can go. Depending on how tight you made the pieces, the puzzle could fall apart at this point - take your time and move slow!

Step 15: Assemble - Step 8

Next, push the highlighted block back as shown.

Step 16: Assemble - Step 9

You are now ready to install the last "keyed" piece. Line up the notch and slide the block down. You can now slide the block over.

Step 17: Assemble - Step 10

Now just reverse the process for the 2 pieces moved in Steps 7 & 8. You have now completed the puzzle!

Step 18: Assembly Steps

The last step is the trick. See video for clarificaton.

Step 19: Option 2 Parts

Use these dimensions if you are starting with 0.75" thick wood. Same build process as Option 1.

Step 20: STP & STL Files

Attachments

Step 21: Pictures Without Finish

Step 22: Sand and Paint/Stain

I made a few versions since I will be giving them away as gifts. I wasn't too happy with the light oak stained version - came out blotchy :(.

Step 23: Painted

I sanded most of the oak stain off and tried paint. I think this one definitely looks nicer. Note that you will need to keep in mind the thickness of paint or stain/poly when working out your dimensions.

Step 24: Christmas Ornaments

The puzzle actually makes a nice ornament for a Christmas Tree. I just wrapped a rope around it but drilling a hole through one of the pieces and tying a decorative string around it would be a better solution.